The party of Aung San Suu Kyi, Myanmar's pro-democracy leader, has threatened to boycott the parliament's opening session set to take place on Monday.

A senior member of the National League for Democracy's executive committee said that its 43 newly elected MPs will not take up their seats unless the military-led government withdraws an oath to "safeguard" the constitution, which Suu Kyi wants amended.

Suu Kyi campaigned in the by-elections on a pledge to amend the country's new constitution which guarantees 25 per cent of all seats to the military.

The NLD has petitioned the constitutional court to change the oath and Suu Kyi has written to Thein Sein, Myanmar's president, asking him to change the oath by replacing it with a pledge to "respect" the constitution instead.

Larry Jagan, a southeast Asia expert and journalist, has told Al Jazeera that he is optimistic that the boycott would not be a major setback for democratic reforms in the country.

"My understanding is that the boycott is going ahead, but I dont think it means the NLD does not want to work with the government on issues that affect people on the ground, like poverty, development and the ceasefire agreements," he said.

"The issue with the oath is just deferring them being sworn in."